JPS588674B2 - Electric motor regenerative braking control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a regenerative braking system using a thyristor chopper device and using a DC motor as the main motor.

It is a well-known fact that when performing regenerative braking using a thyristor chopper, control is possible only in the region where the generated voltage VM on the traction motor side is lower than the power supply voltage VS. A resistor is inserted in series with the traction motor armature to make regeneration more effective.

VM=EA-R(Ω)・IA(A)-・・・(1)
BA=K・Φ(IA)・N・・・・・・・・・・・・(
2) However, VM: Main motor circuit EA: Main motor induced
Generated voltage Voltage R■: Series resistance value K: Constant IA (A): Main motor current N: Main motor rotation
Number Φ (IA): Main motor field magnetic flux.
As shown in equation (1), the resistance terminal voltage drop IA・
R (volt) lowers the traction motor side voltage VM, making regenerative braking possible at higher speeds.

However, when a resistor is permanently inserted, there are problems in that regeneration efficiency decreases due to heat loss in the resistor and that the resistor itself becomes larger.

Conventionally, as a countermeasure to this problem, a switch for shorting the resistor is provided, and the traction motor rotation speed N decreases and the traction motor induced voltage E
A method was considered in which A decreases in proportion to the rotational speed, and when EA becomes lower than the power supply voltage VS, the resistor is short-circuited with a switch, but the moment the resistor is short-circuited, a transient The main motor circuit voltage VM suddenly rises by IA・R (volt), and as a result, the filter capacitor voltage transiently increases.
It has been difficult to realize resistance short-circuit control because there is a risk that the voltage will jump up and apply an abnormally high voltage to the chopper device, causing voltage damage to the chopper device.

Figure 1 shows an example of main circuit connections when a conventional regenerative chopper is applied to an electric vehicle.

In the figure, 1 is a pantograph, 2 is a filter reactor LF
3 is a filter capacitor CF, 4 is a reverse current blocking diode D, 5 is a thyristor chopper CH, 6 is a main smoothing reactor MSL, 7 is a main motor series coil F, 8 is a DC current transformer DCCT, 9 is a main motor Armature A, 10 is series resistor R
shows.

The present invention provides a method that suppresses the above-mentioned rise in filter capacitor voltage, makes it possible to realize resistance short-circuit control, and thereby improves the regeneration rate and makes it possible to downsize the series resistor.

An embodiment of the present invention will be described below based on the drawings.

FIG. 2 shows an example of the main circuit connection according to the present invention.
The same reference numerals as those in the figure indicate the same parts, but in the figure, 11 indicates a resistance shorting switch LS, 12 indicates a reactor RL, and 13 indicates a saturable current transformer SaCT.

In this structure, a reactor 12 is inserted in series with the resistor shorting switch 11, and a time constant of several milliseconds is given to the change in the resistor terminal voltage immediately after the switch 11 is turned on, and a reactor 12 is inserted in series with the resistor shorting switch 11. If the direction of the main circuit current flowing to the saturation current transformer SaCT13 is reversed, the pulse voltage generated in the output winding wound around SaCT is used as a command to forcibly narrow down the conductivity of the chopper 5. The authors' experimental results have revealed that the jump in filter capacitor voltage when a resistor is short-circuited can be largely controlled.

As an example, LF=5mH, CF=3200μF, IA
= 1140A, MSL = 3mH, and R = 0.3Ω. If the conventional method is used, the rise width ΔVCF of the filter capacitor voltage is 240V, but if the method according to the present invention is used and RL = 2mH, ΔVCF is 35V. This is about 1/3 of the conventional method, and it has been confirmed that it is within a range that does not cause any practical problems.

In this case, by inserting the actor 12 and making the rate of change of the resistor terminal voltage somewhat gentler, the forced narrowing control of the current flow rate immediately after the resistor short circuit is performed at exactly the same timing, and transiently stable control is achieved. This is because it becomes possible.

FIG. 3 shows a regenerative chopper control block diagram according to the conventional method, and FIG. 4 shows an example of a regenerative chopper control block diagram according to the method of the present invention.

In the figure, 20 is a main motor current pattern generator, 21 is a comparison amplifier, 22 is a phase shifter, 23 is a chopper main circuit section, 13
is the saturable current transformer CT.

In the method of the present invention shown in FIG. 4, the output pulse of the saturable current transformer CT13 temporarily provides a current narrowing input to both the comparison amplifier and the phase shifter at the same time, so that the chopper current flow rate is immediately adjusted. In addition to narrowing down the parameters, transient stability in control is also ensured.

As described above, by adopting the method of the present invention, it becomes possible to apply regenerative braking more effectively in the high-speed rotation region of the main motor and to improve regenerative efficiency.

[Brief explanation of drawings]

Fig. 1 is a conventional main circuit connection diagram, Fig. 2 is a main circuit connection diagram showing an embodiment of the present invention, Fig. 3 is a conventional control block diagram, and Fig. 4 is a diagram showing an embodiment of the present invention. It is a control block diagram. Note that the same reference numerals in the figures indicate the same or corresponding parts. In the figure, 3 is a filter capacitor, 5 is a chopper, 9 is an armature, 10 is a resistor, 11 is a short circuit switch, 12 is a reactor, 13 is a saturable current transformer, 20 is a main motor current pattern generator, 21 is a comparison amplifier, 22 is a phase shifter, 23
is the Chotupa main circuit section.

Claims (1)

[Claims] 1. In a device that performs regenerative braking control on a DC motor using a thyristor chopper, a resistor is connected in series to the motor armature, and a resistor shorting switch and a reactor are connected in series to the resistor. The circuit includes a saturable current transformer that detects that the resistor shorting switch is turned on, and forcibly and temporarily changes the conduction rate of the thyristor chopper by the output pulse of the saturable current transformer. A regenerative braking control device for an electric motor, which is characterized by performing a narrowing crawler leg.